1. Field of the Invention
The present invention relates generally to IC cards, and more particularly, to an IC card having an improved security checking function.
2. Description of the Background Art
As is well known, an IC card is a card of almost the same size in appearance as those of a cash card and a credit card, which has an IC (integrated circuit) incorporated therein. The IC card is characterized of having significantly larger storage capacity of information, as compared with that of the present card comprising a magnetic stripe. Since various important data are stored in the IC card, it is necessary to care about data security. In the conventional IC card, a security check is performed by the following method. More specifically, when data stored in a storage is accessed, it is determined whether or not a given identification code coincides with an externally applied identification code. If they coincide with each other, reading or writing of data in the corresponding storage area is allowed.
Furthermore, in an IC card which is disclosed in, for example, Japanese Patent Laying-Open Gazette No. 176186/1985, a data storage area in the IC card is divided corresponding to a terminal identification code for identifying the terminal in which the IC card can be used, the IC card itself receives a terminal identification code from the terminal when the IC card is entered in the terminal, and access to only a division area in the data storage area corresponding to the received terminal identification code is allowed.
Out of the above described IC cards, the former has a single identification code. Therefore, if there are a plurality of persons handling a card such as a person issuing a card, a person providing service, and a person having a card, an identification code can not be applied by the persons. Thus, it is difficult to divide an area to be accessed corresponding to the person handling a card. On the other hand, in the latter, an accessible storage area in the IC card is only divided for each terminal. Thus, it is impossible to perform a more detailed check, that is, perform a check of coincidence between an identification code of a person himself or herself using a card and an identification code of the IC card in addition to determination of coincidence between a terminal identification code predetermined for each terminal and a terminal identification code from a terminal, and to allow access if both coincidences are achieved.
Furthermore, in the above described IC cards, when access is allowed by identification of an identification code, all data stored in a storage area where access is allowed can be written and or read, resulting in the problem of lack of data security.